#90 UI: Accept Invitation Page (Public)

Create public Accept Invitation page. Component: api/ui/templates/components/accept_invitation/ Files: - accept_invitation.html - accept_invitation.css - accept_invitation.js URL: #/invite/{token} Features: - Token validation on load - Show invitation details: - Tenant name - Invited by (name) - Assigned role - Expiration status - For New Users: - Name input - Password input with requirements display - Confirm password - OR Google OAuth button - For Existing Users: - Show 'You already have an account' message - Login link - Auto-add to tenant if logged in - Validation: - Password strength meter - Real-time validation feedback - Submit button enabled only when valid - States: - Loading (validating token) - Valid invitation form - Expired invitation message - Already used message - Success with redirect With ultra attention to details and correctness. Before closing: write comment summarizing implementation with screenshot.